Abbreviations:
    3GDT 3G Direct Tunnel    3GPP 3rd Generation Partnership Project    APN Access Point Name    BSC Base Station Controller    CN Core Network    DNS Domain Name System    ECM EPS Connection Management    EMM EPS Mobility Management    EPC Evolved Packet Core    EPS Evolved Packet System    E-RAB E-UTRAN Radio Access Bearer    E-UTRAN Evolved Universal Terrestrial Radio Access Network    GGSN Gateway GPRS Support Node    GTP GPRS Tunnelling Protocol    GTP-U GTP user data tunnelling    GUMMEI Globally Unique MME Identifier    GUTI Globally Unique Temporary Identity    GW Gateway    HLR Home location register    IE Information Element    IM Instant Message    IMSI International Mobile Subscriber Identity    IP Internet Protocol    ISD Insert Subscriber Data    ISRAU Inter SGSN Routing Area Update    MM Mobility Management    MME Serving GPRS Support Node    MME Mobility Management Entity    MS Mobile Station    MT Mobile Terminating    NRI Network Resource Identifier    P GW PDN Gateway    PDP Packet Data Protocol    PDU Packet Data Unit    PLMN Public Land Mobile Network    PS Packet Switched    P-TMSI Packet Temporary Mobile Subscriber Identity    RAB Radio Access Bearer    RAI Routing Area Identity    RAN Radio Access Network    RAT Radio Access Technology    RAU Routing Area Update    RNC Radio Network Controller    S GW Serving Gateway    SRNS Serving Radio Network Subsystem, the change of lu instance and transfer of the SRNS role to another RNS.    TAI Tracking Area Identity    TAU Tracking Area Update    TEID Tunnel Endpoint Identifier    UE User Equipment    UMTS Universal Mobile Telecommunications System    UP User PlaneReferences:    3GPP TS 23.060    3GPP TS 23.401    3GPP TS 29.060    3GPP TS 29.274    3GPP TS 29.272    3GDT is very popular to the operator and the end user. 3GDT enables setup of a GPRS Tunnelling Protocol (GTP) tunnel for transporting payload traffic between a GGSN/PGW or a SGW and an RNC directly, thus bypassing the SGSN. GPRS Tunnelling Protocol (GTP) is a group of IP-based communications protocols used to carry General Packet Radio Service (GPRS) within GSM, UMTS and EPS within LTE networks. The tunnel separates the user traffic from the control traffic and reduces the payload traffic through the SGSN. However, even though the tunnel has many advantages, some complaints from the operators occurs because they found the 3GDT to be consuming a lot of signalling load to the GGSN/PGW or the SGW especially for some IM (Instant Message) applications. The IM applications send very short length of PDU and release the radio connection and reconnect again which gives a lot of signalling load.
In the present existing solution, the SGSN has to handle a high number of (frequent) service requests, which may exhaust the node capacity due to the frequent service request triggered, here called “Update PDP Context Request/Response” between Gn-SGSN and GGSN/PGW or “Modify Bearer Request/Response” between S4-SGSN and SGW.
There is thus a need for an improved and more effective system.